The application of liquid crystal display devices has increased year by year as electric power-saving and space-saving image display devices. It has been considered that liquid crystal display devices have a large drawback, i.e., having a high viewing angle dependency of images. However, VA mode liquid crystal display devices with wide viewing angle become practically usable in recent years and thus the demand for liquid crystal display devices has been rapidly increasing in such a market of, for example, televisions with a need for high-grade images.
In general, VA mode liquid crystal display devices are superior to other liquid crystal display mode devices in having a high contrast. At the same time, however, VA mode liquid crystal display devices suffer from a problem of showing large changes in contrast and hue depending on the viewing angle.
In order to overcome this problem, it has been a common practice to use stretched polymer films as optical compensatory films, since optical compensatory films having uniform qualities can be easily and economically obtained thereby, as disclosed in JP-A-2003-170492 (corresponding to US2003/0020208A1) and JP-A-2006-241293 (corresponding to WO2006/093346A1).
With the recent tendency toward large-screen display devices to be used mainly in big screen TVs, liquid crystal display devices having improved display fidelity are required. Also, optical compensatory films having higher retardation are required. To increase the retardation in such a stretched film disclosed above, it is a common practice to elevate the stretching ratio to thereby elevate the degree of orientation of the polymer in the stretching direction. However, a liquid crystal display device using an optical compensatory film produced by this method has a problem of frequently showing light leakage when lighted over a long time and, therefore, further improvement is needed.